Hot-air furnace



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' C. A. LARSON.

HOT AIR FURNACE. No.499',926. Patented June 20, 1893.

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C. A. LARSoN. HOT AIR FURNAGE. No. 499,926. A v Patented June 20,l 1893.

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UNITED STATES .PATENT OFFICE.

CARL AUGUST LARSON, OF SIOUX-CITY, IOWA.

HOT-AI R FU RNAC E.

SPECIFICATION forming part of Letters Patent No. 499,926, dated J' une20, 1893.

` Application med January 1e, 1893. seria 110.458.577. ou modelo' To @ZZwhom it may concern.-

Beit known that I, CARL AUGUsrLARsoN, a citizen ofthe United States,residing at Sioux City, in the county of Voodbury and State of Iowa,have invented certain new and useful Improvements in Hot-Air Furnaces;and Ido declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same, reference -being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

My invention has reference to hot air furnaces. Its object is to providea furnace that may be simply and cheaplyconstructed, and which willaccomplish most efficient results, and at the same time consume aminimum quantity of fuel. A further Objectis to provide a furnace thatwill produce a `superior draft and utilize almost the entire product ofcombustion before the smoke 'passes into 4the chimney. My furnace alsoprovides a construction by means of which the cold air is thoroughlyheated before it passes into the dome, whence itl is conducted to therooms above. These results are attained by a novel arrangement of thesmoke fines With reference to the cold air draft and also by a novelconstruction of the grate with reference to the cold air chamber.

My invention therefore consists in the novel construction, arrangementand combination of the parts, as will be hereinafter fully described andparticularly pointed out in the claims.

I have fully and clearly illustrated my invention in the accompanyingdrawings, wherein like parts are .designated by similar letters ofreference, in which- Figure 1. is a front view of my furnace inelevation, incased in brick masonry. Fig. 2 is a side view of the samein elevation. Fig. 3. is a vertical section on the left of the fire box,showing the route of the smoke iiues in the smoke chamber. Fig. 4. is avertical section through the center of the furnace, showing the cold airshaft, and cold air chamber, and the tubular construction of one of thegrate-bars. Fig. 5. isa cross-sectional View, with the dome of thefurnace cut away, on line X X Fig. 4, looking down upon smoke flues andgrate. Fig. 6. shows a cross sectional view on line X X of Fig. 4,showing the smoke pipe, centrally located and passing through the coldair shaft. Fig. 7 is a sectional view of fire grate showing tubulargrate bars and clinker bars and shaft. Fig. 8 is afront view of grateframe showing tubular grate bars.

Referring now to the illustrations in detail: C represents thepipeleading to the chimney, in the usual manner.

l K designates the cold air duct and is located above the cellar oor. CC are hot air pipes leading from the dome M to the rooms to be heated. v

d d designates dampers; S the stove door and box through which thefurnace is fed; S the door'and box through which the ashes are removed;H the door through which the hot water pan is lled; A, a door at thebottom through which the furnace is cleaned and which also provides acheck draft; S2 the shaker lever and r the shaker rod.

B B represent the mason work surrounding the furnace and support-ing thefire box; B', an open air space between the masonry, by means of whichthe cold air is excluded and the hot air retained, and all the heatproduced utilized without any great effect upon the furnace room.

F designates the tirebrick and F the lire l box; I the iron frame ofthefire box.

G represents the grate, and G one of the grate bars, which in my furnaceis stationary and for the purpose of procuring the better draft shouldbe placed at an angle with the horizontal plane of the furnace.

r fr are clinker bars attached to the shaker rod, and located betweenthe tubular grate bars.

I represents an iron shield which cuts off the cold air chamber K2, fromthe upper part of the furnace, and is located just above the grate.

P represents a smoke flue passing from right to left on the same planewith pipe P, which leads directly into the chimney, and into which thesmoke passes upon leaving the lire box. On either side of the fire boxand on the same plane, two parallel 'smoke liues extend from the pipe Ptoward the front of the furnace. These pipes are provided at ICO theirouter ends `with dampers d d, and are intersected at o o bythe upperarms cfltwo V shaped smoke fiues o8 o3, one on either side of furnace,curved at o2 o2, which open below into-a smoke chamber K', closed aboveand extending from side to'sideon thesamelcvel with the'cold air shaft.

KS is a hot air chamber, into which the tubular grate bars open, closedjust below they` grate bars, and extending on both sides of the feed boxinto the dome, M. e

D represents a largeedamper whichvmay bef made to open or close the pipeP. By this' damper the draft maybe ma'de topassimme-y smcke'iues into'the smoke chamberus `desired. .y Bhdesignates e small `open spa'ce`through# whicha `smalltqnantity of col'dtairmayepass from` thecold airduct, and which also vcontain .1f pipes. o; and o3, whiclrheatthecoldtairbietorefH it reaches the dome. Y N N are the iron frames whichsupport thei re box lupon' the'brick foundation.` VP2z-is ra@smokepipefleading from the middle ofthe;y smoke chamber K, backthroughthecold-'airi duct:K,vinto the chimney C. y Illhe `operationofsmylinvention `isaslfollowsrl Whenfthefretis justvstarting andraxstrongg 3o quick draft is desired, damper Disfleftfopeni` andthewsmoke'and; gas pass outnbfthe pipe P into the chimney.Whenagocdfreis cre-,kl atedlandit is desired'to usezthe greatestpos-1Asible quantityof heat, damper D `ishelosedff` The colti `aireutersthefuruacei th rou ghfshaftf K, andfenters coldxairchamberlK?. Here itstrikescagainst shieldlf, andiis fcrcedthrough the open ends ofthezgratebar`s1T, cfthegrate bars G" G', where it is thoroughly heated an1d serThisl swift cu rrentof hot ainpasses into cham-E ber `:K-,.aud up intothe idomegwhence iti `passesthrough .the "hot air pipes .C' fC eftotheiroomsabcvc. ,In the meantime :the smoke and gaseous products passiuto1pipes.Pf,then]v the `motion of theheat ,greatlyaccelerateddtothefront through Iiues o o, down ,through fiuesosointo the smoke`chamberlKI The smoke, diffusing heat through pipes o and o3, now passesalong pipe P through the cold air duct into pipe C andout through thechimney. 5o Pipe P2 becomes heated y.and communicates itsheattothe-fcid-airfinf shaft K. The cold air in K, and the hot air in pipe P,proceed- `ting` in lopposite directions, communicate to each other agreater velocity. The, surplus heat from the smoke and gas, are utilizedin .p vheating .thecold ,air-.as vitpzrssesoverppe P2, `tlues o o and c3o?, and through the grate into the dom-e. diately out the chimney, ordown through the `By reference to the construction of my fur- 6o znaceit will be.-seenzzthatbut asmall tportion of A itis constructedcftironofrariyakind. .Aside frcmithe rdcors aand llanxesrthe `iron tfrre:1 box, lfines*andgratgfthevfurnacexslmayfheiconstructed en trety :ofshriek. ,{Ehistmateiial renders `65 -lithe 41consti-'11ction `Nerylsiniple, durable fand` .'cheap.` i x lwingfthusfullmandrelearlydescrihedmry iinventiomwlratInciaimrasmlewfandiiiesireito`fsecurebyLettersiPateut,sis- `17e il. `:In :a 'hottairitnrmarcwthe!`double furn ace iframe-direboxyandistatioxmryxtubular grate,

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.12. rlinsafhot airifurnaceymith-doubieiframe, Afire ..1box, "dome,:coldrair `shaft a'nd .cold `mir :cham ber,'the.combination ofiues Pf,-o 0,03 013, .s 8c smoke :chamber AfKQ:and@pipesLPfandi (5.; with` 'thetubularrgratelGnpassingffrcm :lacoldiair`LchamberiK?,atoihoteiir31mmberrK?, substantillyffasfspecitied.'

l CARL AUGUST aLASON. "Witnesses:

iL.. S. SBEARSON,

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